Cosmic ray electron spectrum due to the dispersion of injection spectrum

The cosmic-ray total electron spectrum(electrons plus positrons) has been measured precisely up to Te V energies,with more interesting features found.Exhaustive analyses of the electron spectrum strongly support a spectral hardening above 100 GeV,rather than a featureless single power-law,which is confirmed by the most recent observations.Meanwhile,the measurements of the DAMPE satellite have verified the presence of a knee-like structure around 1 TeV in the electron spectrum,resembling the cosmic-ray knee.In this paper,we establish a physical model in which the observed electron spectrum is composed of a superposition of CR sources with various spectral indices and high-energy cutoffs.The dispersion of the power index is assumed to be Gaussian,while the cutoff energy Ec follows a power-law distribution.These simple ideas can account naturally for both the hundred-GeV excess and the TeV spectral break.     

Representations obeying the spectrum condition

We show that every properly infinite, injective von Neumann algebra acting on a separable Hilbert space is isomorphic to the weak closure of some translation covariant representation, obeying the spectrum condition for the generators of the translation group, of theC*-algebra of quasilocal observables of a free massless spinor field. We construct explicitly such representations in the case ofII andIII factors, 0<<1.     

The extensive air shower muon number spectrum beyond the knee in the cosmic-ray energy spectrum

The extensive air shower (EAS) muon number spectrum is obtained with increased statistics using the central muon detector of the EAS MSU array, which records muons with energies above 10 GeV. The dependence of the mass composition of primary cosmic rays on the energy is considered. The conclusion is confirmed that for energies from 3 × 10¹⁵ eV (the primary energy spectrum knee) up to 10¹⁷ eV a change in the composition associated with an increase in the proportion of heavy nuclei occurs; however, after the energy of 10¹⁷ eV, the proportion of heavy nuclei begins to decrease and the composition becomes lighter. A comparison with similar data from other experiments is conducted. The existence of an additional component of cosmic rays is confirmed; earlier an indication of its presence was derived from data on the EAS electron number spectrum.     

Microwave spectrum and hyperfine structure in the rotational spectrum of diatomic gallium iodide

The J = 3←2 rotational transition of diatomic GaI molecule has been measured in the microwave region. The molecules were produced by a reaction of gallium and lead iodide in the heated zone of a splitted wave guide. The lines were observed in the 10-GHz frequency region at a reaction temperature 270–350°C. Molecular parameters have been derived for ⁶⁹Ga¹²⁷I and ⁷¹Ga¹²⁷I from the analysis of the hyperfine structure. Systematic variations in quadrupole coupling constants in III_a halides have been observed. Vibrational dependence of the nuclear quadrupole interaction for ⁶⁹Ga¹²⁷I can be written as follows: $\text{eq}{}_{\mathrm{<mtext>v</mtext>}}\text{Q(}{}^{69}\text{Ga}\text{) = ?81.29(25) + 0.43(30)(v +}\text{1}\text{2}\text{)}\text{MHz}$, $\text{eq}{}_{\mathrm{<mtext>v</mtext>}}\text{Q(}{}^{127}\text{I}\text{) = ?369.35(10) ? 2.54(16)(v +}\text{1}\text{2}\text{)}\text{MHz}$.     

原子的吸收光谱和发射光谱的演示

介绍了利用光学多道分析仪和投影仪在课堂上实时演示原子的吸收光谱和发射光谱的实验方法。     

宽谱段光学系统消二级光谱的设计

利用修正的部分色散(P)和阿贝数(V)公式,计算一些典型的普通光学玻璃在450nm～950nm波段的色散特性,应用二级光谱理论,采用普通光学材料,设计了一个复消色差系统,分析近红外波段光学系统的二级光谱特性及校正方法,给出设计实例。设计结果表明:在可见光近红外波段,采用重冕玻璃ZK4、ZK8和特种火石玻璃TF3组合实现了二级光谱色差的校正,即从理论的0.18mm减少到0.084mm,证明该系统有较好的消色差能力,并且具有较长的后截距,为安装像移补偿反射镜提供了方便。     

Plasmaneutrino spectrum

The spectrum of the neutrinos produced in the massive photon and longitudinal plasmon decay process has been computed with four levels of approximation for the dispersion relations. Some analytical formulae in the limit cases are derived. Interesting conclusions related to previous calculations of the energy loss in stars are presented. The high energy tail of the neutrino spectrum is shown to be proportional to exp(-E/kT), where E is the neutrino energy and kT is the temperature of the plasma. PACS 97.90.+j; 97.60.-s; 95.55.Vj; 52.27.Ep     

Meson spectrum

Using the Klein-Gordon equation with a box potential, a mass formula describing the family of nonflavored meson states withI=1 is derived. The energy levels calculated agree with those observed within an accuracy of 5%. In the model discussed quarks behave like tachyons.     

On the spectrum of the Rayleigh piston

We make a rigorous study of the spectrum of the Rayleigh piston. Our main results are that one is dealing with a trace-class perturbation for all values of the mass ratio y between test particles and heat bath particles and that apart from the ground state the discrete spectrum is empty for y sufficiently near 1. We also show that the so-called Lorentz limit ( ) is mathematically well defined and derive a qualitative statement on the discrete spectrum of the scattering operator for 1.     

On the spectrum of the Heisenberg Hamiltonian

The quantum, antiferromagnetic, spin-1/2 Heisenberg Hamiltonian on thed-dimensional cubic lattice ^d is considered for any dimensiond. First the anisotropic case is considered for small transversal coupling and a convergent expansion is given for a family of eigenprojections which is complete in all finite-volume truncations. Then the general case is considered, for which an upper bound to the ground-state energy is given which is optimal for strong enough anisotropy. This bound is expressed through a functional involving the statistical expectation value at finite temperature of a certain correlation function of an Ising model defined on the lattice ^d itself.     

Modeling the THz spectrum of the bentazon

Terahertz (THz) spectra of bentazon are determined within the range of 0.3 2.4 THz at room temperature.Density functional methods are used to compute the THz spectra using three different programs:Gaussian03 for isolated-molecule form,DMol 3 and CRYSTAL09 for solid-state forms.Among the three,the computed THz spectrum of CRYSTAL09 shows better bond length and angle agreements with Xray experimental results,and corresponds with observed THz experiment spectral characteristics.The isolated-molecule vibrational mode values are less by half than those derived from solid-state calculations.The last five peak positions of the two solid-state computations coincide with each other.Moreover,all the experimental THz absorption peaks are assigned by utilizing CRYSTAL09.     

Comparison between the time-integrated spectrum and the peak time spectrum of gamma-ray bursts and possible implications

The mono-frequency peak luminosity and the corresponding photon energy of the time-integrated(Ls p,Es p)and peak time(Lt p,Et p)νfνspectra were derived for a sample of 38 redshift-known Fermi GRBs by fitting the spectra with the Band function.It was found that Et pis generally consistent with Es p,and Lt pis averagely three times larger than Ls p.The slope of the Lt p-Et prelation was consistent with that of the Ls p-Es prelation.The photon indices in the peak time spectrum,particularly,the index of the low energy end was,were statistically larger than that in the time-integrated spectrum.These results indicate that Ls pand Es pare dominated by Lt pand Et p,respectively.The difference of the spectral indices between the time-integrated and peak time spectra may be because of the overlap effect of a series of time-resolved spectra within a GRB.Our simulations,which were based on the observed spectral evolution and correlation between the energy flux and the peak energy within individual GRBs support our speculations.The Lt p-Et prelation may be less contaminated by the overlap effect,and it would may be an intrinsic feature of radiation physics.     

Self-broadening of the ammonia inversion spectrum

We show that self-broadening of the ammonia inversion lines with J = K can be explained by taking account of the rotational resonance effect.     

Collimator-size effect on the parametric-radiation spectrum

It is shown that, by varying the angular size of a collimator, the spectral distribution of parametric x-ray radiation can be split into two isolated peaks and that the center of the spectral distribution of this radiation is shifted in frequency in response to an increase in the collimator size. It is also predicted that an increase in the angular size of the collimator will lead to a substantial modification of the character of the orientation dependence of the radiation spectrum.